JPH0718500Y2 - Biting prevention device for automatic screw tighteners - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is an automatic screw tightening machine for automatically tightening screw parts such as cross-shaped screws, hexagon socket screws or bolts After the screw tightening work,
The present invention relates to a compact bite prevention device configured to smoothly release biting between a driver bit and an engaging portion of a screw head when the driver bit returns.

[Conventional technology]

Generally, an automatic screw tightener is configured to transmit the rotation of a rotary drive source transmitted via a built-in torque clutch mechanism to a driver bit. The hexagon socket head screw comes into contact with the work and begins to be screwed into the work.After that, when the screw is completely screwed into the work, the torque clutch mechanism operates to block the rotation of the driver bit. There is.

When tightening the screw in place with this kind of automatic screw tightening machine, there is no problem until the screw is tightened with the driver bit, but when the screwdriver bit goes up and returns to the original position after the tightening is complete, The head hole of the screw bit and the tip of the driver bit stick to each other, the head hole of the screw may be damaged, or the entire work may be pulled up. There is a problem such as damage to the tip.

In order to solve this problem, the one disclosed in JP-A-62-199328 has recently been developed. This is the third
As shown in FIGS. 4 and 5, a guide shaft 2 is fixed to the bracket 1, and a driver base 5 and a catcher base 3 to which a rotary drive source 6 is fixed are fixed to the guide shaft 2.
Are independently or independently driven by the elevation source B and are slidably guided. The driver base 5 has a built-in lock means for forcibly engaging the meshing drive clutch 8 that meshes during screw tightening and the meshing driven clutch 9 when the driver base 5 retracts. This locking means is operated by an external piston cylinder 4.

On the other hand, a catcher 30 that holds one screw is attached to the catcher base 3, and the screw of this catcher 30 is suction-held by a suction sleeve 31 and carried to a predetermined position, and then,
It is designed to be tightened with a driver bit 22.

[Problems to be solved by the invention]

However, with such a configuration, the upper part of the automatic screw tightener inevitably becomes large, especially when tightening the hexagon socket head screw in a multi-axis automatic screw tightener, attach a piston cylinder to each driver body. Since it has to be carried out, there is a problem that the whole automatic screw tightening machine becomes larger than the conventional one and the installation space becomes wider.

The present invention has been devised for the purpose of solving such a problem.

[Means for solving problems]

In order to achieve this object, according to the present invention, a rotary drive source 6 is fixed to a movable driver base 5 by a lifting source B, and a meshing drive clutch 8 is connected to a drive shaft 7 of the rotary drive source 6, On the other hand, one side is provided with this meshing drive clutch 8 and the other side is provided with a meshing driven clutch 9 forcibly meshing with the lock teeth 11a of the driver body A. Further, the meshing driven clutch 9 is provided with an inclined cam groove 21. In the automatic screw tightener in which the meshing driven shaft 15 having the formed guide cylinder 20 is connected, and the locking pin 23 is planted in the driver bit 22 so as to rotate integrally with the driven shaft 15 of the cam groove 17 of the guide cylinder 20. An outer cylinder 13 fixed to the driver base 5 on the outer periphery of the meshing drive clutch 8.
The inner cylinder 12 fixed to the inner cylinder 12 is arranged, and the push piston 14 which is slidable in the axial direction is inserted between the inner cylinder 12 and the outer cylinder 13, and one end of the push piston 14 meshes with the driven clutch. The configuration is such that 9 is pushed.

[Action]

The rotary drive source 6 operates, the meshing drive clutch 8 rotates, and the driver main body A moves forward together with a catcher base to which a catcher holding one screw is attached. As a result, the driver bit 22 and the suction sleeve 31 that holds the screw 41 from the middle further descends even if the catcher 30 stops. Then, the suction sleeve 31 is stopped immediately before the workpiece 40 comes into contact with it, and the screw 41 is pressed against the workpiece 40 by the driver bit 22. Therefore, the driver main body A and the driver bit 22 move relative to each other, while the pushing piston 14 is retracted, so that the meshed driven clutch 9 is caused by the above operation.
Moves backward and meshes with the meshing drive clutch 8. Then, the driver bit 22 rotates and the screw 41 is screwed into the work 40.

In this way, when the screw 41 is tightened with a predetermined tightening torque, the driver body A rises and the push piston 14 advances, and the meshed driven clutch 9 locks the lock member 11.
And the meshed driven clutch 9 is fixed to the driver main body A. After that, when the driver body A continues to rise, the locking pin 23 of the driver bit 22 moves along the inclined cam groove 21 of the guide cylinder 20, so that the driver bit 22 tilts in the direction of the loosening of the screw. Reverse only the corner. As a result, the engagement between the driver bit 22 and the engaging hole in the head of the screw 41 is released, the driver body A is retracted to its original position, and the screw tightening operation is completed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In FIG. 1, 5 is a driver base, and a rotary drive source 6 incorporating a torque clutch mechanism (not shown) is fixed to the upper part of the driver base 5 via a lock member 11 and an outer cylinder 13. . A meshing drive clutch 8 having meshing teeth at the tip is connected to the drive shaft 7 of the rotary drive source 6, and the meshing drive clutch 8 can mesh with the teeth on the same center line. A meshing driven clutch 9 having teeth is arranged. In this meshed driven clutch 9, the guide shaft portion 9a has a guide hole 8a in the meshing drive clutch 8.
It is elastically urged and is inserted. Further, on the front surface of the outer peripheral portion of the meshed driven clutch 9, there are formed lock teeth 11a having a rectangular or sawtooth cross section in a direction along the circumference. The lock teeth 11a are formed around the meshed driven clutch 9. The lock member 11 fixed to the driver base 5 can be meshed with the other lock tooth 11b formed at a position opposite to the lock tooth 11a of the meshed driven clutch 9. Further, the tip of a pushing piston 14 is in contact with the rear surface of the outer periphery of the meshing driven clutch 9, and the pushing piston 14 is disposed on the outer side of the meshing driving clutch 9 and further outside thereof. It is reciprocally inserted between the cylinder 13 and the cylinder 13. That is, the inner cylinder 12 and the outer cylinder 13 form a cylinder, and the cylinder and the pushing piston 14 form the piston cylinder 10. The pushing piston 14 of the piston cylinder 10 is set so as to move up when the lifting source B moves down and move down when the lifting source B moves up.

On the other hand, a driven shaft 15 is connected to the meshed driven clutch 9, and a guide cylinder 20 is attached to the driven shaft 15. A cam groove 21 is formed in the guide cylinder 20 to rotate the driver bit 22 in its loosening direction when a locking pin 23, which will be described later, descends relative to the guide cylinder 20. The locking pin 23 implanted in the driver bit 22 is engaged so as to project.

Next, the operation of this embodiment will be described. When the hexagon socket head screw 41 is supplied to the catcher 30, the lift source B operates and the driver main body A moves down together with the driver base 5. At this time, the piston cylinder 10 operates and the pushing piston 14 moves up to release the engagement of the meshed driven clutch 9. Then, along with this, the rotary drive source 6 rotates, and the meshing drive clutch 8 rotates. Thus, as shown in FIG. 2, the driver body A descends, the screw 41 is adsorbed in the adsorption sleeve 31, and the screw 41 is held at the tip of the driver bit 22.
Then, when they come into contact with each other, the meshing driven clutch 9 rises due to the relative movement with the driver bit 22, and the lock teeth 11a and 1
The meshing with 1b is released, and meshing with the meshing drive clutch 8, the rotation is transmitted to the driver bit 22. Thereafter, the suction sleeve 31 stops descending, and when the driver body A descends in this state, a preset thrust is applied to the driver bit 22 to screw the screw 41 into a predetermined position on the work 40. Begin to. At this time, driver body A
Since the descending speed of the driver bit 22 is slower than the descending speed of, the driver bit 22 relatively rises. In this way, when the screw 41 is screwed into the predetermined position with the predetermined torque, the rotation of the driver bit 22 is stopped. When the raising / lowering source 2 starts the returning operation, the piston cylinder 14 also operates at the same time, the pushing piston 14 descends, and the meshing driven clutch 9 is pushed down to mesh with the meshing driven clutch 9.
The lock tooth 11a and the lock tooth 11b of the lock member 11 mesh with each other to prevent the driven clutch 9 from rotating.

If the ascent continues in this state, the locking pin 23 moves along the cam groove 21, the driver bit 22 reverses, and the tip of the driver bit 22 and the screw 41 do not bite. In this state, the driver main body A and the suction sleeve 31 are raised, so that the nape 41 and the work 40 are not damaged at all.

[Effect of device]

As is apparent from the above-described embodiments, the present invention has a driver body A in which the pushing operation of the meshing driven clutch 9 to the lock teeth 11a for releasing the engagement between the screw and the driver bit 22 is built in the driver body A. Dynamic piston 14, inner cylinder 12 and outer cylinder 13
It is configured to be performed by the piston cylinder 10 configured in.

Therefore, it is possible to smoothly release the bite of the driver bit on the screw head that occurs when the screw is tightened in a predetermined position by the driver bit, and the driver bit breaks the head of the screw after the screw is tightened. Not only is this eliminated, but the rise of the driver bit is not stopped by the work into which the screw is screwed, and the work is not damaged, and the number of defective products can be drastically reduced. However, by using the device of this structure, the automatic screw tightener becomes almost the same size as the conventional one, and the driver body of the automatic screw tightener does not become large. Further, even in the multi-axis automatic screw tightening machine, since the size hardly changes, the installation space becomes constant, and the installation work can be performed smoothly.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of the present invention, FIG. 3 is a sectional view showing an operating state of the present invention, FIG. 3 is an overall view of a screw tightening machine showing a conventional example, and FIG. 4 is a main part of a conventional example. FIG. A is a driver main body, B is a lifting source, 1 is a bracket, 2 is a guide shaft, 3 is a catcher stand, 4 is a piston cylinder,
5 is a driver base, 6 is a rotary drive source, 7 is a drive shaft, 8 is a meshing drive clutch, 9 is a meshing driven clutch, 10 is a piston cylinder, 11 is a lock member, 11a and 11b are lock teeth,
12 is an inner cylinder, 13 is an outer cylinder, 14 is a pushing piston, 15 is a driven shaft,
20 is a guide tube, 21 is an inclined cam groove, 22 is a driver bit,
23 is a locking pin, 30 is a catcher, 31 is a suction sleeve, 40
Is a workpiece, 41 is a screw,

Claims (1)

[Scope of utility model registration request] 1. A rotary drive source (6) is fixed to a driver base (5) which is movable by a lifting source (B), and a meshing drive clutch (8) is connected to a drive shaft (7) thereof. A meshed driven clutch (9), which is forcibly meshable with the meshing drive clutch (8) on one side and the lock tooth (11b) on the driver body (A) on the other side, is arranged in front of the meshing clutch (8). The driven shaft (15) having the guide cylinder (20) having the inclined cam groove (21) formed therein is connected to the driven clutch (9), and the driven shaft (15) is connected to the inclined cam groove (21) of the guide cylinder (20). ) So that it rotates together with the driver bit (22).
In the automatic screw tightening machine in which 3) is planted, the inner cylinder (12) fixed to the outer cylinder (13) fixed to the driver base (5) is arranged on the outer periphery of the meshing drive clutch (8). An axially slidable push piston (14) is inserted between the inner cylinder (12) and the outer cylinder (13), and one end of the push piston (14) meshes with the driven clutch (9). A bite prevention device characterized by being configured to push.